1. Field of the Invention
This invention relates to the field of laser and optical instruments and more particularly to the field of interferometric systems that require a control to peak the response of a laser signal source such as the signal output from an active linear or ring laser gyro, or the mode of fequency dithering of a passive interferometer.
2. Prior Art
Interferometric control assemblies typically have a frame or body, on which a multi-layer dielectric mirror is centrally formed, with a flat mounting surface. The flat surface is typically bonded to an end or corner of an optical cavity in an interferometer, or laser, or ring laser gyro body. The mirrors are used to reflect light passing through the cavity incident on the mirrored surface. The mirrored surface is typicallly formed on a thin wall that serves as a diaphragm to permit slight motion of the mirrored surface as part of the cavity. A PZT (piezoelectric transducer), that is attached to the diaphragm, is driven with an electrical control signal to move the diaphragm to thereby shorten or lengthen the optical pathlength to optimize the resonance of the cavity.
The path length control provided by conventional control assemblies makes no provision for correcting small reflective angle misalignment caused by inherent fabrication misalignment in the cavity and by bending effects in the laser cavity or diaphragm mirror. Mirror alignment is made costly during the fabrication of the interferometer because provision is not usully made for correcting the interferometer alignment dynamically during operation.